Chapel Hill, NC, September 9, 2009 – Cempra Pharmaceuticals today announced that enrollment is underway in an adaptive design Phase 2/3 clinical study with CEM-102 for patients suffering from acute bacterial skin structure infections (ABSSI). CEM-102 is an oral antibiotic with an established record of treating staphylococcal infections outside the United States, including those due to methicillin-resistant Staphylococcus aureus (MRSA). It is effective against all staphylococci, including hospital-acquired MRSA (HA-MRSA) and community-acquired MRSA (CA-MRSA). Cempra has the exclusive source to the antibiotic and has advanced the development of the compound in the United States, including formulation development, to minimize resistance development.

“It is well-known that MRSA and bacterial resistance against the current arsenal of antibacterials are rising at alarming rates, and new antibiotics, especially oral drugs, are needed to combat this growing problem,” notes Dr. Prabhavathi Fernandes, CEO of Cempra Pharmaceuticals. “This compound, previously approved outside the United States to treat staphylococcal infections, has shown activity against a range of difficult-to-treat and drug-resistant infections, and Cempra is advancing CEM-102 in a proprietary dosing regimen to address the resistance issues we are seeing in both hospital and community settings today. We are essentially giving new life to an established oral drug that is known to be safe.”

The first of two pivotal trials is an adaptive design, randomized, double-blind, multi-center study to evaluate the safety and efficacy of orally-administered CEM-102 compared to linezolid in the treatment of ABSSIs. Cempra estimates enrollment of 880 patients with a diagnosis of an ABSSI that would be expected to require 10 to 14 days of antibacterial therapy. Dr. Gordon Still, CMO of Cempra said, “As of today, the study is ahead of projected patient enrollment timelines and interim data are expected by year end.” The study will measure treatment success rates in the clinically evaluable and intent-to-treat patient populations at the test of cure visit.

In addition to CEM-102, Cempra’s lead macrolide, CEM-101, will soon enter a Phase 2 clinical trial for moderate to moderately-severe community-acquired bacterial pneumonia. Both CEM-102 and CEM-101 will potentially address key antibacterial needs identified by the Infectious Disease Society of America. Cempra completed a $46 million Series C financing in 2009 that will fund the further development of these compounds.

About Cempra Pharmaceuticals

Founded in 2006, Cempra Pharmaceuticals is a privately-held, clinical-stage biotechnology company focused on developing two antibacterials to address critical medical needs. These lead products, both in late-stage clinical trials, address the urgent and increasing need for new treatments targeting drug-resistant bacterial infections in the hospital and in the community. Cempra is well-funded and is committed to developing commercially viable products through consideration of pricing and reimbursement issues throughout its products’ lifecycles. The company is also utilizing its proprietary chemistry technology to develop macrolides without antibacterial activity for non-antibiotic uses in motilin receptor activity, anti-inflammatory activity and GnRH receptor antagonism. Additional information about Cempra can be found at www.cempra.com.